Mankind has needed to lift heavy things throughout history. When the things that needed lifting were more than a single man or group of men could lift, mankind designed machines for lifting. One of those machines was the block and tackle. A significant mechanical advantage could be obtained by using blocks with rotating pulleys linked together with rope or line tackle. There are limitations to the number of pulleys that one can put in a block as at some point, the friction from the line and pulleys in the blocks cannot be overcome. The industry then began using bearings in the pulleys. While this did reduce the friction in the block and tackle systems even a bearing system had frictional limitations.
Many new advances have been made in the rope or line industry. Some of the new lines available are very slippery. Applicant recognized this and has designed a new type of block and tackle system that takes advantage of the slickness of the rope or line. This new block does not need bearings to function and can provide mechanical advantage with much simpler components and fewer moving parts.